Battery cell, method and system for manufacturing battery cell, battery, and electrical device

This application is a continuation of International Patent Application No. PCT/CN2021/097225, filed on May 31, 2021, which is incorporated herein by reference in its entirety.

This application relates to the technical field of batteries, and more specifically, to a battery cell, a method and system for manufacturing same, a battery, and an electrical device.

Battery cells are widely used in electronic devices such as a mobile phone, a notebook computer, an electric power cart, an electric vehicle, an electric airplane, an electric ship, an electric toy car, an electric toy ship, an electric toy airplane, and a power tool. The battery cells may include a nickel-cadmium battery cell, a nickel-hydrogen battery cell, a lithium-ion battery cell, a secondary alkaline zinc-manganese battery cell, and the like.

In the development of battery technology, safety is a non-negligible issue in addition to improvement of the performance of the battery cell. If the safety of the battery cell is not guaranteed, the battery cell is not suitable for use. Therefore, how to enhance the safety of the battery cell is an urgent technical issue in the battery technology.

This application provides a battery cell, a method and system for manufacturing same, a battery, and an electrical device to enhance safety of the battery cell.

According to a first aspect, an embodiment of this application provides a battery cell, including:

A first recess is formed on a side that is of the second side plate and that faces the electrode assembly, and the first recess is configured to accommodate at least a part of the electrode assembly.

In the foregoing solution, by disposing a duct on the support member, this embodiment of this application can guide the gas into the pressure relief mechanism, where the gas is released by the battery cell during thermal runaway. In this way, the pressure relief mechanism is actuated in time to release the gas. On the premise that a volume of the electrode assembly is constant, in this embodiment of this application, a first recess is made on the second side plate to accommodate at least a part of the electrode assembly, thereby increasing the spacing between the electrode assembly and the first side plate in the first direction and vacating more space for the support member. Correspondingly, a duct of a larger size can be made on the support member, so as to increase the gas exhausting rate during thermal runaway of the battery cell on the basis of ensuring a relatively high capacity of the battery cell, and improve safety of the battery cell.

In some embodiments, the duct is formed between the support member and the first side plate. In this embodiment of this application, a first recess is made on the second side plate to accommodate at least a part of the electrode assembly, thereby increasing the spacing between the electrode assembly and the first side plate in the first direction and vacating more space for the support member. The duct is formed between the support member and the first side plate, and the dimension of the duct along the first direction can be increased correspondingly, so as to increase the gas exhausting rate of the duct during thermal runaway of the battery cell, and improve the safety of the battery cell.

In some embodiments, the support member is spaced apart from the first side plate in the first direction to form the duct between the support member and the first side plate. A gap is formed between the surface of the support member and the first side plate, the surface facing the first side plate. In this way, the gas exhausting space between the support member and the first side plate is increased, and the gas exhausting rate of the battery cell during thermal runaway is increased.

In some embodiments, the support member includes a first surface and a second surface disposed opposite to each other. The first surface faces the first side plate and abuts against the first side plate, and the second surface faces the electrode assembly. The support member includes a second recess, and the second recess sinks against the first surface along a direction back from the first side plate. At least a part of the second recess overlaps the pressure relief mechanism in the first direction; and the second recess forms at least a part of the duct.

The second recess can guide the gas into the pressure relief mechanism, thereby facilitating actuation of the pressure relief mechanism and release of the gas. The second recess provides a mounting space for the pressure relief mechanism, thereby reducing risks of the support member squeezing or blocking the pressure relief mechanism. By making the second recess, a weight of the support member can be reduced, and an energy density of the battery cell can be increased.

In some embodiments, the second recess runs through the support member along a second direction, and the second direction is perpendicular to the first direction. The space on both sides of the support member along the second direction can communicate with the second recess, so that the gas inside the battery cell can flow into the second recess more easily.

In some embodiments, in the first direction, a depth of the second recess is less than or equal to a depth of the first recess. In this embodiment of this application, the second recess is enlarged by the space vacated by the first recess. The depth of the second recess is less than or equal to the depth of the first recess, thereby ensuring a relatively high capacity of the battery cell.

In some embodiments, at least one support portion is disposed on a bottom wall of the second recess, and the support portion is configured to abut against the first side plate. The second recess includes a first part and a second part. The first part and the second part are located on two sides of the support portion respectively. The first part covers the pressure relief mechanism in the first direction. The second part is staggered from the pressure relief mechanism in the first direction.

The support portion disposed according to this embodiment of this application can increase the overall strength of the support member, reduce risks of deformation and collapse of the support member, and improve stability.

In some embodiments, the support portion includes a communication structure.

The communication structure is configured to implement mechanical communication between the first part and the second part. The communication structure forms a part of the duct.

The communication structure disposed according to this application enables flow of gas between the first part and the second part, thereby increasing gas exhausting paths, and increasing the gas exhausting rate during thermal runaway of the battery cell.

In some embodiments, the support member further includes a third recess. The third recess sinks against the second surface along a direction back from the electrode assembly. The third recess is configured to guide the gas in the electrode assembly into a space between the second side plate and the support member.

During thermal runaway of the battery cell, high-temperature and high-pressure substances such as gas are ejected from both ends of the electrode assembly along the first direction. The third recess can guide the gas, which is ejected from the electrode assembly, into the space between the second side plate and the support member, so that the blocking of gas by the support member is alleviated, and the gas exhausting rate is increased.

In some embodiments, the third recess runs through the support member along a second direction, and the second direction is perpendicular to the first direction.

The third recess runs through the support member along the second direction. Therefore, the space on both sides of the support member along the second direction can communicate with the third recess, and the gas released by the electrode assembly can more easily flow through the third recess into the spaces located on two sides of the support member along the second direction.

In some embodiments, at least one through-hole is made on the support member, and the at least one through-hole runs through the support member along the first direction to communicate with the duct.

With the through-hole, the space between the second side plate and the support member can communicate with the duct. When the battery cell is thermally runaway, the electrode assembly ejects gas toward the support member. A part of the gas can flow through the through-hole into the duct and act on the pressure relief mechanism, so as to be quickly released after the pressure relief mechanism is actuated.

In some embodiments, the shell assembly further includes two third side plates disposed opposite to each other along a second direction. The third side plates are connected to the first side plate and the second side plate, and the second direction is perpendicular to the first direction. In the second direction, an exhaust gap is provided between at least one of the third side plates and the support member. The exhaust gap communicates with the duct and is configured to guide the gas between the second side plate and the support member into the duct.

With the exhaust gap, the space between the second side plate and the support member can communicate with the duct. When the battery cell is thermally runaway, at least a part of the gas released by the electrode assembly can act on the pressure relief mechanism through the exhaust gap and the duct, so as to be released in time after the pressure relief mechanism is actuated.

In some embodiments, the second side plate includes an end cap and an insulation piece. The insulation piece is located on a side that is of the end cap and that faces the electrode assembly, and the insulation piece forms the first recess on the side that faces the electrode assembly.

In some embodiments, the insulation piece includes a first body and a first bulge. The first body includes a first inner surface and a first outer surface opposite to each other. The first inner surface faces the electrode assembly. The first bulge is disposed protrusively on the first outer surface. The first recess is formed on a side that is of the first bulge and that faces the electrode assembly, and sinks against the first inner surface. A fourth recess is formed on a side that is of the end cap and that faces the electrode assembly. The fourth recess is configured to accommodate the first bulge.

The first bulge can exert a reinforcing effect on the position at which the first recess is disposed. In addition, the first bulge disposed can cause the first recess to sink as far as possible along a direction back from the electrode assembly, so as to increase the depth of the first recess and provide more space for the duct. The first bulge is accommodated in the fourth recess, so as to reduce the internal space occupied by the insulation piece, and further vacate more space for the electrode assembly and the support member, and in turn, increase the gas exhausting rate on the basis of ensuring a relatively high capacity of the battery cell.

In some embodiments, the end cap includes a second body and a second bulge. The second body includes a second inner surface and a second outer surface opposite to each other. The second inner surface faces the first body and fits snugly with the first outer surface. The second bulge is disposed protrusively on the second outer surface. The fourth recess is formed on a side that is of the second bulge and that faces the electrode assembly, and sinks against the second inner surface.

The second bulge exerts a reinforcing effect on a position at which the fourth recess is disposed on the end cap. In addition, the fourth recess can sink as far as possible along the direction back from the electrode assembly, so as to accommodate the first recess.

In some embodiments, the second side plate further includes an electrode terminal mounted on the end cap. The electrode terminal is configured to electrically connect to the electrode assembly. Along a protrusion direction of the second bulge, the second bulge does not protrude beyond the electrode terminal. Therefore, even if the second bulge is disposed on the end cap, a maximum dimension of the battery cell in the first direction will not be increased, thereby ensuring a relatively high energy density of the battery cell.

In some embodiments, the insulation piece further includes a third bulge. The third bulge and the first bulge are located on two sides of the electrode terminal respectively. The third bulge is disposed protrusively on the first outer surface. The end cap further includes a fifth recess. The fifth recess sinks against the second inner surface. The fifth recess is configured to accommodate the third bulge.

The third bulge disposed can increase the overall strength of the insulation piece, and reduce the deformation of the insulation piece during the assembling. The third bulge and the fifth recess can serve a positioning function during the assembling of the insulation piece and the end cap. The third bulge may be in interference fit with the fifth recess, so as to implement fixing between the insulation piece and the end cap.

According to a second aspect, an embodiment of this application provides a battery, including the battery cell according to any embodiment according to the first aspect.

According to a third aspect, an embodiment of this application provides an electrical device, including the battery according to the second aspect. The battery is configured to provide electrical energy.

According to a fourth aspect, an embodiment of this application provides a method for manufacturing a battery cell, including:

The first side plate and the cover assembly are located on two sides of the electrode assembly along a first direction respectively. The support member is disposed between the electrode assembly and the first side plate, and configured to support the electrode assembly. The duct is configured to guide gas between the cover assembly and the support member into the pressure relief mechanism, so that the pressure relief mechanism is actuated to release a pressure when the pressure reaches a threshold. The first recess is formed on a side that is of the cover assembly and that faces the electrode assembly. The first recess accommodates at least a part of the electrode assembly.

According to a fifth aspect, an embodiment of this application provides a system for manufacturing a battery cell, including:

The first side plate and the cover assembly are located on two sides of the electrode assembly along a first direction respectively. The support member is disposed between the electrode assembly and the first side plate, and configured to support the electrode assembly. The duct is configured to guide gas between the cover assembly and the support member into the pressure relief mechanism, so that the pressure relief mechanism is actuated to release a pressure when the pressure reaches a threshold. The first recess is formed on a side that is of the cover assembly and that faces the electrode assembly. The first recess accommodates at least a part of the electrode assembly.

The drawings are not drawn to scale.

To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following gives a clear description of the technical solutions in the embodiments of this application with reference to the drawings in the embodiments of this application. Evidently, the described embodiments are merely a part of but not all of the embodiments of this application. All other embodiments derived by a person of ordinary skill in the art based on the embodiments of this application without making any creative efforts fall within the protection scope of this application.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as usually understood by a person skilled in the technical field of this application. The terms used in the specification of this application are merely intended for describing specific embodiments but are not intended to limit this application. The terms “include” and “contain” and any variations thereof used in the specification, claims, and brief description of drawings of this application are intended as non-exclusive inclusion. The terms such as “first” and “second” used in the specification, claims, and brief description of drawings herein are intended to distinguish between different items, but are not intended to describe a specific sequence or order of precedence.

Reference to “embodiment” in this application means that a specific feature, structure or characteristic described with reference to the embodiment may be included in at least one embodiment of this application. Reference to this term in different places in the specification does not necessarily represent the same embodiment, nor does it represent an independent or alternative embodiment in a mutually exclusive relationship with other embodiments.

In the description of this application, unless otherwise expressly specified and defined, the terms “mount”, “concatenate”, “connect”, and “attach” are understood in a broad sense. For example, a “connection” may be a fixed connection, a detachable connection, or an integrated connection; or may be a direct connection or an indirect connection implemented through an intermediary; or may be internal communication between two components. A person of ordinary skill in the art understands the specific meanings of the terms in this application according to the context.

The term “and/or” in this application indicates merely a relation for describing the related items, and represents three possible relationships. For example, “A and/or B” may represent the following three circumstances: A alone, both A and B, and B alone. In addition, the character “/” herein generally indicates an “or” relationship between the item preceding the character and the item following the character.

In embodiments of this application, the same reference numeral denotes the same component. For brevity, detailed descriptions of the same component are omitted in a different embodiment. Understandably, dimensions such as thickness, length, and width of various components in the embodiments of this application shown in the drawings, and dimensions such as overall thickness, length, and width of an integrated device are merely exemplary descriptions, but do not constitute any limitation on this application.

“A plurality of” referred to in this application means two or more (including two).

In this application, a battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, or the like. The embodiments of this application do not limit the type of the battery cell. The battery cell may be in a cylindrical shape, a flat shape, a cuboidal shape, or other shapes. The embodiments of this application do not limit the shape of the battery cell. Depending on the form of packaging, the battery cell is typically classed into three types: cylindrical battery cell, prismatic battery cell, and pouch-type battery cell. The embodiments of this application do not limit the form of the battery cell.